Conventional air conditioning systems use freon, a compressor and a fan which are powered by electricity. The cost of the freon and the compressor has always been high. In addition, the amount of electricity needed to power the compressor has always been substantial. In the past decade, however, the cost of electricity and the materials used to manufacture conventional air conditioning systems have increased dramatically.
One way in which to lower the costs of cooling a building is to replace the expensive compressor and freon with a less expensive cooling medium. One such cooling medium is the ground beneath the earth. At a depth of six feet, in the temperate zone, the earth has a relatively constant temperature of approximately 57.degree. F.
Many cooling systems have been manufactured which use the ground beneath the earth as a cooling medium to cool a building. However, these cooling systems are still relatively expensive and not very efficient. For example, the patent to ROGERS et al., U.S. Pat. No. 4,234,037, discloses a set of pipes which carry air from a building to a location beneath the ground and then return the air to the building. However, the transfer of heat through the pipes to the ground is not very efficient. ROGERS et al., in fact, states that in many applications his cooling system can only act as a supplement to and not replace a conventional cooling system.
The patent to TROYER, U.S. Pat. No. 4,323,113, forces air into a heat exchanger 14 buried beneath the ground, which contains heat transfer material 52 such as crushed brick, stones, or a plurality of vessels containing water. The air passes over and between material 52 to become cooled. The TROYER patent, while more efficient than ROGERS et al. is still relatively inefficient and is also expensive. The housing for heat exchanger 14 must be made of concrete to hold the heat transfer material 52. Furthermore, once the material 52 is heated by contact with the warm air, this heat is not dissipated very quickly and therefore the device only has a limited capacity for cooling. In addition, these rocks in heat exchanger 14, or even the vessels containing water in heat exchanger 14 are not mobile and therefore cannot be moved to other locations to cool additional air.
The patent to SUO, U.S. Pat. No. 4,258,780, is directed to a cooling device that must be used with a heat pump and a heat exchanger 19 in a building 20. Fluid from the heat pump travels beneath the ground to exchange heat with a second fluid in pipes 4. Fluid such as freon in pipes 4 has a low boiling point, so that it becomes vaporized upon contact with the first fluid, thereby absorbing the heat from the first fluid. When the second fluid vaporizes, it travels up pipe 4, dissipating its heat, condensing and returning to the bottom of pipe 4. Although SUO shows a somewhat efficient means of dissipating the heat in the fluid beneath the ground, SUO is relatively expensive, because it requires the use of a heat pump and a heat exchanger in the dwelling and the use of expensive freon. In addition, SUO uses needless electricity to run the heat pump and heat exchanger.
Thus, there is a need for a low-cost cooling unit consuming a small amount of energy, which efficiently dissipates the heat of the building beneath the surface of the earth.